1. Field of the Invention
The present invention relates to a liquid crystal display (“LCD”) device and, more particularly, to an LCD having a data driver that performs a charge sharing function.
2. Discussion of the Related Art
An LCD device includes a thin film transistor (“TFT”) substrate and a color filter substrate on which electric field generating electrodes are formed. A liquid crystal is injected between the two substrates arranged to face each other. The LCD device displays an image by varying the light transmittance of the liquid crystal in accordance with an electric field applied between the electrodes that changes the orientation of the liquid crystal molecules when a voltage is applied to the electrodes.
An LCD panel comprises a plurality of pixels provided at the intersections of the data lines and gate lines, a data driving unit for applying a data signal to the data line, a gate driving unit for applying a gate driving signal to the gate line, a timing controller for controlling the data and gate driving units, and a power supply unit for supplying a driving voltage to the LCD panel.
The LCD device is driven in an alternating current (“AC”) signal applying method that applies electric fields to adjacent pixels in a direction different from each other in order to prevent polarization of the liquid crystal and to improve display performance.
Methods of applying AC signals to the pixels includes a dot inversion method that drives the liquid crystal panel by inverting the polarities of voltages applied to adjacent dots, a line inversion method that inverts the polarities of voltages applied to adjacent gate lines, a column inversion method that inverts the polarities of voltages applied to adjacent data lines, a frame inversion method that inverts the polarities of voltages applied to all the pixels once per frame time, and the like.
In the related art charges may be shared among respective data lines by shorting the data lines connected to a data driving unit before the gradation voltage corresponding to the display data is applied to the data lines. However, when the respective data lines are shorted, the charge share level between the first and last data lines is different from that of a data line positioned in the middle. This is because the first and last data lines perform the charge sharing with an adjacent data line unlike the data line located in the middle.
The difference in the charge share level causes a difference in the amount of pixel charge and, results in a vertical line defect when the LCD panel is driven by a plurality of data driving integrated circuits.